X-ray apparatus with interchangeable filter and area dose measuring device

Abstract

An X-ray apparatus has a radiation source, an interchangeable radiation filter and an area dose measuring device having a measurement chamber with an allocated evaluation device for determining the area dose product on the basis of a measured signal provided by the measurement chamber. The measurement chamber is arranged preceding the filter in the beam path with reference to the radiation propagation direction. A detector recognizes the nature and / or the type of radiation filter that is currently inserted in the beam path. The evaluation device corrects the area dose product that is calculated from the measured signal from the measurement chamber on the basis of at least one filter-specific correction value that is selected as a result of the detection of the filter nature and / or type.

Description

BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention is directed to an X-ray apparatus of the type having a radiation source, an interchangeable radiation filter and an area dose measuring device with a measurement chamber and an allocated evaluation device for determining the area dose product on the basis of the measured signals provided by the measurement chamber, with the measurement chamber arranged preceding the filter in the beam path with reference to the radiation propagation direction.2. Description of the Prior ArtMeasurement of the area dose product allows determination of the amount of X-radiation applied to the examination subject, for example a patient. This measurement is conventionally undertaken with an area dose-measuring device having a measurement chamber that is arranged in the beam path. This measurement chamber usually is an ionization chamber through which the X-rays pass and at which an output signal dependent on the amount of radiation...

AI Technical Summary

Benefits of technology

An object of the present invention is to provide an X-ray apparatus that eliminates the aforementioned disadvantage associated with known X-ray apparatus in the determination of the area dose.

In the inventive X-ray apparatus, the detector makes it possible to determine what filter type or what kind of filter is inserted into the beam path following the measurement chamber. On the basis of this knowledge, which is forwarded to the evaluation device, the evaluation device is able to suitably correct the area dose product that is calculated in the evaluation device based on the signal acquired by the measurement chamber preceding the radiation filter. This correction is undertaken using at least one filter-specific correction value, i.e. a correction value that takes the filter properties of the recognized filter into consideration. As a result, it is possible to calculate the filter effect of the following radiation filter and to include this in the calculated area dose product. This product thus indicates the actually applied X-rays as accurately as possible, rather than the unattenuated amount of radiation.

In order to recognize the nature or type of filter, it is necessary to be able to identify each inserted or insertable filter so that its filter-specific features or characteristics can be likewise identified. In a first embodiment of the invention, the detector for recognizing the nature and / or type of filter can be a transponder arranged at the filter and an acquisition device that picks up the transponder signal. This acquisition device, which can also be the corresponding excitation device, activates the transponder to emit the transponder signal. The acquisition device can be external to the surface dose-measuring device or the evaluation device itself can be fashioned for this purpose. Each radiation filter has its own filter-specific transponder, so that a simple acquisition and discrimination are possible.

Problems solved by technology

Due to this arrangement wherein the radiation filters follow the measurement chamber, the problem arises that the filter effect does not enter into the determination of the area dose product.

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